I read somewhere that the human brain doesn’t fully mature until 25, which might explain why so many people get into a bad situation with debt in early adulthood. This would also explain why I completely spunked the lump sum my grandma gave me when I was 18.
With 15-20 years of hindsight, if I had money to give my future grandchild I would probably keep the money in my name for another 7 years till the child’s brain has finished growing, but invest it in a small portfolio of dividend paying shares, maybe 5 ftse250 listed shares (not too big to have the lowest yield, not too small to be overly risky or hard to trade).
These days most brokers will let you specify an account for the dividends to be paid to, so if you set that to your son’s account he could have small amounts of £30-50 dropping into the account 10 times a year (if those companies pay interim and final dividends). You might also find that in 7 years the value of the portfolio may have grown as well. Obv it could fall as well but with time that is less likely.